Abstract Background Health utility values are required for cost-utility analyses in breast cancer, yet EQ-5D-5L-based health utility estimates and validity evidence across clinically relevant health states remain limited. The objectives of this study were to estimate health utility values for pre-defined breast cancer health states using the EQ-5D-5L (EuroQoL 5-level) instrument and to investigate its construct validity in breast cancer. Methods This cross-sectional study included women with invasive breast cancer, who completed both EQ-5D-5L and the Edmonton Symptom Assessment System. Participants were classified into five pre-defined health states, considered relevant both to clinical practice and economic modeling. We used the Canadian EQ-5D-5L value set to calculate community-valued health utility scores for each health state. Additionally, we evaluated aspects of construct validity (known-group and convergent validity) of EQ-5D-5L in breast cancer. Results 549 women were included; the mean age was 57 (SD 12) years. The mean EQ-5D-5L index score was 0.83 (SD 0.13; range 0.13 to 0.95), with a distribution skewed towards full health and a ceiling effect of 20%. The mean health utility value for early-stage breast cancer was 0.84 (95% CI 0.83–0.86) and for metastatic breast cancer was 0.78 (95% CI 0.76–0.81). This difference was 0.060 (lower 95% CI bound 0.036, slightly lower than the pre-specified minimum important difference of 0.037). Health utility values and ESAS scores met almost all pre-specified criteria for convergent validity. Conclusion We generated a list of health utility values for five pre-defined breast cancer health states using EQ-5D-5L. Additional research is required to confirm the validity of EQ-5D-5L as an outcome measure in breast cancer.
Torres et al. (Fri,) studied this question.